That's "D" for Dunston. So why not "G" for Garth? Dunston and Garth, not Dunston and Matt,.
I think Matt as a kid asks to have the brand M on his cow. Basically that was the letter he chose as a boy.
shareI reacted the same way. Burns and Gracie? Astaire and Ginger? Martin and Jerry? But here's another problem: Why is it the Red River brand at all? Dunston's ranch is quite clearly stated to be on the Rio Grande. This is an important plot point in that he steals the land from it's "rightful" Mexican owner. The Rio Grande is the southern border of Texas, while the Red River is its northern border. Yes, crossing the Red River in the cattle drive is the Rubicon on which the plot rests, but Dunston had no idea how important that river was to become when he designed the brand.
shareIs the Dunston ranch on the Rio Grande, or extending as far south as the Rio Grande, or several hundred miles north of the Rio Grande?
Based on the 10-12 miles a day that the cattle could travel, and the ~90 days that the drive took, I'd estimate that they started from somewhere west or slightly northwest of San Antonio. If south of there, then it would have taken much longer.